1. Field of the Invention
The present invention relates generally to a technique for wrapping a sheet about an external surface of a flexible member, and more specifically to an apparatus for entraining the flexible member and the sheet about support means so that the flexible member is wrapped about itself and the sheet serves to substantially prevent any point of the flexible member external surface from touching any other point of the flexible member external surface.
2. Description of the Prior Art
In the art of electrophotography an electrophotographic plate comprising a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging the imaging surface of the photoconductive insulating layer. The plate is then exposed to a pattern of activating electromagnetic radiation such as light, which selectively dissipates the charge in the illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in the non-illuminated area. This electrostatic latent image may then be developed to form a visible image by depositing finely divided electroscopic toner particles on the surface of the photoconductive insulating layer. The resulting visible toner image can be transferred to a suitable receiving member such as paper. This imaging process may be repeated many times with reusable photoconductive insulating layers.
The electrophotographic plate may be in the form of a flexible photoreceptor belt. These flexible belts include a substrate and a sensitive layer, the sensitive layer including an electrically conductive surface and at least one photoconductive layer. A common flexible photoreceptor belt comprises a substrate, a conductive layer, an optional hole blocking layer, an optional adhesive layer, a charge generating layer, a charge transport layer and, in some embodiments, an anti-curl backing layer.
These photoreceptor belts are usually thin and flimsy. Any considerable amount of handling of the belt, through, for example, shipping, can result in damage to the sensitive layer. Scratches, dents and other forms of damage to the sensitive layer, resulting from handling, can lead to degradation in image quality in printed material produced by the printing machine. Additionally, handling of the belt is made more difficult when the belt is in an unraveled state.
A proposed approach for eliminating the above-discussed difficulties has been disclosed in U.S. Pat. No. 5,119,133 to Swain the relevant portions of which are incorporated by reference herein. In particular, a photoconductive belt covered by protective paper is extended about first and second cores. The second core is inserted in a C-shaped hollow core, the C-shaped core having a slot configured to prevent the escape of the second core therefrom. When the second core is disposed in the C-shaped core, the belt extends through the slot. In operation, the C-shaped core is rotated, so that the first core is drawn toward the C-shaped core. When the first core is proximate to the C-shaped core, the belt is fully entrained about the three cores, and the second core is nested in the C-shaped core. The first core and the C-shaped core are held together by a U-shaped clip.
Another proposed approach for eliminating the above-discussed difficulties is to manually entrain the belt and a sheet of protective paper about a plurality of cores or cardboard tubes in such a way that no point of the sensitive layer surface touches any other point of the sensitive layer surface. In one example, first, second and third cores are respectively positioned on first, second and third mandrels, and the cores are disposed adjacent one another. A gap is formed between the first and second cores, and a free edge of a sheet of protective paper and a portion of the belt is then clamped between the first and second cores. After straightening out the belt, by moving; the third core away from the second core, the first and second cores are rotated simultaneously about an axis disposed between the first and second cores. As the first and second cores are rotated simultaneously, the third core is drawn toward the second core until the protective paper and the belt are entrained completely about the cores in the above-described manner.
While these proposed approaches result in an adequately wrapped belt, manual entraining of the belt about the cores is undesirable. In particular, manual entraining is labor-intensive. Moreover, the proposed approaches do not minimize manufacturing costs. Regarding the first approach, manufacturing costs are increased by both the use of the customized C-shaped core and the need to adhere protective backing to the outer, sensitive surface of each belt. Regarding the second approach, cost is increased when more than one belt size must be wrapped since various sets of mandrels must be employed and various lengths of precut sheets of protective paper must be kept in stock. It would be desirable to provide a belt-wrapping apparatus that minimizes manufacturing costs substantially and eliminates the need to perform wrapping steps manually. Accordingly, all steps would be achieved automatically using both relatively cheap components and a single supply of protective paper capable of being cut into sheets of varying length.
The following references may be pertinent to the present application:
U.S. Pat. No. 3,942,637; Patentee: Glennie; Issued: Mar. 9, 1976. PA1 U.S. Pat. No. 3,984,241; Patentee: Schrempp et al. Issued: Oct. 5, 1976. PA1 U.S. Pat. No. 4,162,009; Patentee: Schouten; Issued: Jul. 24, 1979. PA1 U.S. Pat. No. 4,219,272; Patentee: Brukel et al. Issued: Aug. 26, 1980. PA1 U.S. Pat. No. 4,416,532; Patentee: Rosati; Issued: Nov. 22, 1983. PA1 U.S. Pat. No. 4,707,704; Patentee: Allen et al. Issued: Nov. 17, 1987. PA1 U.S. Pat. No. 4,912,510; Patentee: Ogura et al. Issued: Mar. 27, 1990. PA1 U.S. Pat. No. 4,926,216; Patentee: Hashimoto et al. Issued: May 15, 1990.
U.S. Pat. No. 3,942,637 discloses a packaging configuration for endless nested abrasive belts, which configuration includes a first core having an axial slot to receive axially within the first core one end of a nest of belts. The belts are wound around the first core and a second core is disposed in the opposite end of the belts. A third core inserted in the nest of belts and disposed in the loop within the first core further restricts kinking of the belts.
U.S. Pat. No. 3,984,241 discloses an apparatus and method for continually replacing a photoconductor belt with incremental fresh segments from a cartridge.
U.S. Pat. No. 4,162,009 discloses a packaging configuration for an endless fabric material used in paper making machines, which configuration includes two inner cores at the extreme ends of the endless fabric. One end of the endless fabric is inserted into a third, larger core, the third core having a split and hinged construction. The remaining fabric is wound around the outside of the third core. The two inner cores may be mounted on stringing poles during winding to minimize deflection of the cores. If the cores are sufficiently rigid, they are inserted directly in chuck jaws. The ends of the assembled inner cores may be banded together to prevent unrolling and the banded assembly may be wrapped with a protective cover.
U.S. Pat. No. 4,219,272 discloses an electrophotographic copying apparatus comprising a replaceable photoconductive sheet having a leading edge portion and a trailing edge portion. The apparatus further includes a guide drum rotatably supported to a drum shaft, a holding device for securing the leading sheet edge to the guide drum and a pressing roller which guides and engages the sheet.
U.S. Pat. No. 4,416,532 discloses a free end of a cantilever-mounted photoconductor belt capstan rigidly secured to a machine frame by a pivotable mechanism including a slide pin and dog arrangement for cooperating with a receiving block on the machine frame. This mechanism is arranged to operate a tension applying/relieving shoe against the inner surface of the photoconductor belt.
U.S. Pat. No. 4,707,704 discloses a paper material drive mechanism associated with a rotatable drum. The drum carries three rollers: an idler roller, a tension roller and a drive roller. The idler roller and the tension roller are each biased toward the drive roller to provide traction for the movement of the paper.
U.S. Pat. No. 4,912,510 discloses a photosensitive sheet located in a cartridge, which cartridge is located in an image forming apparatus. The cartridge is comprised of a box for containing a roll of unused photosensitive sheet and a shaft, the shaft being used to wrap up used portions of the photosensitive sheet. The shaft has adhesive sections so as to wrap the used photosensitive sheet securely.
U.S. Pat. No. 4,926,216 discloses a feeder of sheet-like photosensitive materials to a drum in an electrophotographic printer. In accordance with the invention, sheet-like photosensitive materials, each cut to a necessary length, are stuck to release paper and are then formed to assume a rolled configuration. The outer peripheral end of the previously rolled release paper is seized by a roll, and the sheet-like photosensitive material can be fed sheet by sheet to the drum by taking up the release paper while rotating the roll.